What medium are you using to report your temps?
My K8T Neo has very unreliable sensors and use Motherboard Monitor now as it took putting a temp probe into the various areas to ascertain that CoreCentre is a bit all over the place when it comes to temps.
My Neo's core centre was telling me that I was near burnout, time and again, sent me frantic with worry, went and bought a water cooling setup cursing the name of Artic Freezer Pro 64 as I went, then did a hard check and found that the Freezer was returning something like 32 degrees and the water system about the same, stuck on MBM and got the same readings as the thermal probe I taped to the CPU board next to the die, CoreCentre was saying something like 65 degrees.
As from switching from Pink Chewing gum pad to a reasonable compund, yes you would likely see a major change as the bubblegum stuff is bred for reliabilty over years but with loss of performance, thermal compounds are bred with the highest performance in mind but be advised that some super duper compounds can run off the chip in vertical systems and also dry out quicker so need replacing more frequently.
AO